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Finding the Fourth Proportional to 915.10, 1,372.65 and 853.90

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Solution

The fourth proportional to 915.10, 1,372.65 and 853.90 is: 1,280.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.10 : 1,372.65 = 853.90 : x
  2. Step 2: Convert to fraction form
    915.10/1,372.65 = 853.90/x
  3. Step 3: Cross multiply
    915.10x = 1,372.65 × 853.90
  4. Step 4: Simplify right side
    915.10x = 1,172,105.84
  5. Step 5: Solve for x
    x = 1,172,105.84/915.10
  6. Step 6: Final answer
    x = 1,280.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.